La0.6Sr0.4Fe0.8Ni0.2O3-δ perovskite with in-situ exsolved Ni-Fe nanoparticles as high activity catalyst for symmetric solid oxide electrolysis cells

• Published in: Materials research bulletin 2022-12, Vol.156, p.111984, Article 111984
• Main Authors: Wang, Xiang, Yang, Zhibin, Wang, Haoran, Zuo, Yi, Zsurzsan, Gabriel, Zhang, Zhe
• Format: Article
• Language: English
• Subjects: co-electrolysis; in-situ exsolution; SOEC; steam electrolysis
• ISSN: 0025-5408; 1873-4227
• DOI: 10.1016/j.materresbull.2022.111984

•FeNi3 nanoparticles were in-situ exsolved on the surface of the perovskite after treatment.•LSFN have excellent oxygen ion transport capability as air electrodes in an oxidizing atmosphere.•Reduced LSFN have high catalytic activity as fuel electrodes in a reducing atmosphere. Effective electrode materials play a key role to enhance electrochemical performances of symmetric solid oxide electrolysis cells (SSOECs). Herein, “exsolution effect” of perovskite oxide at high temperature and reducing atmosphere is introduced. As a proof, La0.6Sr0.4Fe0.8Ni0.2O3-δ(LSFN) perovskite decorated with in-situ exsolved Ni-Fe alloy nanoparticles is reported as electrode materials of SSOECs. XRD, SEM, TEM, and XPS characterizations prove the formation of Ni-Fe alloy. The as-prepared SSOECs deliver improved electrochemical performances for both steam electrolysis (50%H2O/50%H2) and co-electrolysis (50%H2O/40%CO2/10%H2), current densities of 0.64 and 0.67 A·cm−2 are obtained at 1.3 V and 800°C, respectively. Electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) analysis show that the in-situ formed Ni-Fe nanoparticles can provide a new reaction path for water/hydrogen half-reaction, and electrochemical activity and kinetics of oxygen evolution reaction (OER) can be significantly enhanced by RP type perovskite oxide after re-oxidation treatment. Moreover, the SSOECs successfully runs for 60 h at 1.2 V without obvious performance degradation. [Display omitted]